Hagen Aquarium Hydrometer Plus

8in floating hydrometer/thermometer. Proper salt content is vital to the health and well being of captive marine species. Use the Hagen aquarium hydrometer to determine the specific gravity of marine water aquariums on an ongoing basis. Ensure all replacement water has the same salinity as the aquarium.

Hagen Aquarium Hydrometer Plus 8in
Hagen Aquarium Hydrometer Plus 12in